[thekhegay]

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• The commit message follows our guidelines: https://github.com/nestjs/docs.nestjs.com/blob/master/CONTRIBUTING.md

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Docs
• Other... Please describe:

What is the current behavior?

Issue Number: N/A

OpenTelemetry page says the loader flag is only needed for ES module build. On Nest 12 CommonJS build (nest new --type cjs) still loads @nestjs/* as ES modules (@nestjs/platform-express is "type": "module" and does import express from 'express'), and --require hook only sees require(). So with CommonJS commands from the page Express is not patched, there are no instrumentation-express spans and HTTP span is POST instead of POST /orders. Same with importing instrumentation.ts on first line of main.ts

What is the new behavior?

Hint says CommonJS build on Nest 12 needs the loader flag as well, and the first-line import note says it is not enough for Express there. Checked on Nest 12.3.2 with auto-instrumentations-node 0.82.0 and sdk-node 0.300.0, Node 24: adding --experimental-loader=@opentelemetry/instrumentation/hook.mjs to CommonJS command brings Express spans and POST /orders back

Does this PR introduce a breaking change?

• Yes
• No